Rebrand Perl plugin to HexChat,

Add /pl and plugin_pref

Add help messages
Add chanview files to project
Add preference to change tabs on scroll

Also revert e52905f50c7ff5d123a58ba016dcbb9de2b13f4f
Fix scroll buttons when using tabs
Work around for /away being called multiple times

This will have to be solved eventually in menu.c so you can change their
status without emitting the signals.
Round 3 of Gtk accessor functions: xtext
Revert 2d5cb3ec7bc62e5c4e7b550ecade22bb53efd9f6

Scrolling has issues i couldn't easily fix, will get back to
later but lets keep this usable
Improve Windows installer

- Unify x86 and x64 installer files
- Get rid of version program
- Clean up .iss file
- Only allow one installation
Fix messages with server-time not showing as new activity

Added a parameter to fe_print_text() to say that the message does not represent
new activity. This is used when a log from an old session is loaded. This used
to be implicit whenever the timestamp was non-zero, but with server-time this no
longer makes sense.

Fixes issue #746.
Remove left over ifdef for spellcheck
Add hexchat perl module to gitignore
Fix a few cppcheck warnings.

Use the proper data type in format functions and fix a resource leak.
Fix configure output when python disabled
xtext: store palette as GdkColors
Better understandable option for the input box's color rendering
Merge pull request #801 from Phr33d0m/patch-2

Better understandable option for the input box's color rendering
Fix installer on 32bit Windows
Rename Strawberry to Hexchat in Perl error message
win32: Make all projects depend on common so that common is always run before any others.
win32: Use version information from configure.ac to populate the Windows-specific files that need it - config-win32.h, version.txt, hexchat.rc, hexchat.iss

This is done via T4 templates. The original files are now generated at build-time and so have been added to .gitignore and removed from the repository, with the exception of version.txt which must be hosted on GitHub for the updater plugin.