Fix build 2 errors on Fedora

add boost-devel to linux autobuild script and include string.h to png target.
Make toolbox translatable again.
Add appdata file

Applications wishing to have long descriptions, screenshots and other useful things
are required to ship one or more files in /usr/share/appdata/%{id}.appdata.xml.
see pttp://people.freedesktop.org/~hughsient/appdata/
Merge pull request #86 from jcome/jcome

Fix build 2 errors on Fedora
Linux build script: Add support for ALT Linux
Linux package: Update buildroot version to Debian Lenny
Win32 build script cleanup
New crosscompile script for creating linux packages.

Benefits of new approach:
* No root prevelegies required
* Allows to build from current working tree
* No need to create full package to test modifications
* Allows to build with custom library set, without affecting system libraries
* Easy to debug
Keep improving Linux packaging script
OSX build: Bump MacPorts version
Use small buttons for toolbars. Fixes #512 for Win32 case.
Fix nasty crashes in Linux build by updating the acient version of libsigc++
Linux build TODO notes
Linux build: Revert to the bundled version of libpng