0024722: Move functionality of WOK command wgendoc to OCCT tool gendoc

Command gendoc improved to:
- generate Reference Manual documentation (OCCT classes reference) with option -refman; option -overview can be used for generation of overview documentation;
- generate PDF documents for all User Guides automatically (for files listed in FILES_PDF.txt);
- check availability of third-party tools (Doxygen, Inkscape etc.) and properly report warnings and errors.
- use templates of configuration files for third-party tools instead of their generation. These template files are located in dox/resources folder

Tcl scripts are moved from dox folder to adm.
Doxygen warnings are eliminated.
Moved all auxilary functions to occaux.tcl.
Fixed Reference manual generation on *nix platform.
Fixed PDF generation on *nix platforms.

dox/dev_guides/git_guide/git_guide.md

@@ -1,4 +1,4 @@
-Guide to installing and using Git for OCCT development {#dev_guides__git_guide}
+Guide to installing and using Git for OCCT development {#occt_dev_guides__git_guide}
 =================================
 
 @tableofcontents 
@@ -307,7 +307,7 @@ Click on that tab, then click **Add a public key**, and paste the text of the pu
     > git clone gitolite@git.dev.opencascade.org:occt <path>
 ~~~~~
 
-  where <i><path></i> is the path to the new folder which will be created for the repository.
+  where <i>\<path\></i> is the path to the new folder which will be created for the repository.
     
   * In TortoiseGit: create a new folder, open it and right-click in the Explorer window, then choose **Git Clone** in the context menu: