documentation updated

unrelated changes: Unused unit OpenCL removed from UDLIST

All articles revised
README revised
comments are allowed in FILES.txt

Add gendoc.sh for Linux
Added option -s to set search engine of the HTML documents
Added 3rdparty_building docs for different platforms

help message removed from bat&sh scripts (left within tcl script)
tableofcontents added for all huge articles;
gendoc.bat doesn't change PATH variable
jpgs converted to pngs and unused pngs removed
logo displaying of pdf files fixed
Automatic detection of OCCT version number added to occtdoc.tcl
OCCT version within pdfs is got from Standard_Version.hxx; copyright changed
pdf generation process removes latex dir now
GIF images converted to PNG in technical_overview;
references fixed (incorrect reference to wok and cdl didn't touch; redundant latex option removed

Tutorial moved from Overview and made top level page
LICENSE.md moved from dox/overview to dox folder

Section related to OCCT building refactored and simplified.
WOK and CDL explicitly declared as deprecated.

dox/dev_guides/dev_guides.md

@@ -1,79 +1,17 @@
  Developer Guides {#dev_guides}
 ================
 
-## Source Repository
+The following documents provide information on OCCT building, development and testing:
 
-This directory contains sources of Open CASCADE Technology (OCCT), a collection
-of C++ libraries providing services for 3D surface and solid modeling, CAD data
-exchange, and visualization. OCCT can be best applied in development of
-software dealing with 3D modeling (CAD), manufacturing / measuring (CAM) or
-numerical simulation (CAE).
+* @subpage dev_guides__building "Building OCCT from sources"
+* @subpage dev_guides__documentation "Documentation system"
+* Coding Rules
+* Contribution Workflow
+* Guide to installing and using Git for OCCT development
+* @subpage dev_guides__tests "Automatic Testing system"
 
-The OCCT code is subject to the Open CASCADE Technology Public License Version
-6.6 (the "License"). You may not use the content of the relevant files except in
-compliance with the License. Please see the LICENSE file or obtain a copy of the
-License at http://www.opencascade.org and read it completely before using this
-software.
+Two other documents provide details on obsolete technologies used by OCCT, 
+to be removed in future releases:
 
-## Automatic tests
-
-OCCT automatic testing system is integrated with @ref draw "DRAW Test Harness",
-a console application based on Tcl (a scripting language).
-All tests are run from DRAW command prompt (run **draw.bat** or 
-**draw.sh** to start it).
-
-Standard OCCT tests are located in subdirectory **tests** of the OCCT root 
-folder. This location is set as default at DRAW start (see environment variable 
-_CSF_TestScriptsPath_ defined in **src/DrawResources/DrawDefaults**).
-
-The tests are organized in three levels:
-- Group: a group of related test grids, usually testing a particular subset of OCCT functionality (e.g. *blend*). 
-- Grid: a set of test cases within a group, usually aimed at testing a particular aspect or mode of execution of the relevant functionality (e.g. *buildevol*).
-- Test case: a script implementing an individual test (e.g. *K4*).
-
-To run all tests, type command *testgrid*:
-
-    Draw[]\> testgrid
-
-For running only a group or a grid of tests, give additional arguments indicating the group and (if needed) the grid name:
-
-    Draw[]\> testgrid blend simple
-
-As the tests progress, the result of each test case is reported. 
-At the end of the log a summary of test cases is output, including the list of 
-detected regressions and improvements, if any.
-The tests are considered as non-regressive if only OK, BAD (i.e. known problem), 
-and SKIPPED (i.e. not executed, typically because of lack of a data file) 
-statuses are reported. 
-
-To run a single test, type command 'test' followed by the names of 
-group, grid, and test case. 
-
-    Draw[1]\> test blend simple A1
-    CASE blend simple A1: OK
-
-To see intermediate commands and their output during the test execution, 
-add one more argument '-echo' at the end of the command line, or type 'dlog get'
-after test completion. 
-
-For more information consult \subpage dev_guides__tests
-
-## docs
-**short description**
-
-\subpage dev_guides__documentation
-
-## wok
-**short description**
-
-\subpage dev_guides__wok
-
-## building
-**short description**
-
-\subpage dev_guides__building
-
-## cdl
-**short description**
-
-\subpage dev_guides__cdl
+* @subpage dev_guides__wok "Workshop Organization Kit (WOK)"
+* @subpage dev_guides__cdl "Component Definition Language (CDL)"