Place where dot executable is found

In the current vhdl part of the code it is required that the dot executable is in the path. On in dot.cpp the possibility exists that the dot executable is found through the configuration setting DOT_PATH.
This patch makes this more consistent
A new files have been added but is not incorporated in the windows build part

The build references for htmlentity.{cpp,h} were missing for windows builds
Superfluous backslash in documentation

Some superfluous backslashes were found in the documentation (1.8.6 manual page 52, diagrams section)
Command \< and \> are not properly shown in section headers (and consequently in index)

In the pdf version of the doxygen manual (version 1.8.6) the commands \< and \> are shown as < and >
Tests (on the doxygen manual) revealed that the exception rules were nor required.
Made documentation more consistent

Made documentation for custom commands more consistent and remove not required backslashes
Properly escape the XCODE path.

This was causing problems on my system where Xcode is installed at
/Applications/Xcode 5.0/
Pull out property names in Objective-C.

Property names are everything after the ::.
Merge pull request #114 from albert-github/feature/bug_vhdl_dot

Place where dot executable is found
Merge pull request #115 from albert-github/feature/bug_html_entities_build

A new files have been added but is not incorporated in the windows build part
Merge pull request #116 from albert-github/feature/bug_docu

Superfluous backslash in documentation
Merge pull request #117 from albert-github/feature/bug_docu_latex

Command \< and \> are not properly shown in section headers (and consequently in index)
Merge pull request #118 from albert-github/feature/bug_docu_custcmd

Made documentation more consistent
Merge pull request #119 from NimbusKit/xcodeescape

Properly escape the XCODE path.
Merge pull request #120 from NimbusKit/propertynames

Pull out property names in Objective-C.