Remove prebuilt submodule
Add scripts for building pre-builts
Add a script for packaging pre-builts
Update .gitignore to ignore the prebuilt binaries
Add support for custom archs and compilers for prebuilts
Don't forget to package the prebuilt headers
Update installer and buildscripts for moved prebuilts
Fix packaging for Win32 libCurl
Add a script for fetching libraries from server
(Temporarily!) re-add some pre-built binaries

"Temporarily" because it is hoped something can be done to get rid of these soon...
Ignore the "fetched" folder in prebuilt
Merge remote-tracking branch 'upstream/refactor-syntax_unicode' into feature-rejig-prebuilts

Conflicts:
	prebuilt
	thirdparty
Merge pull request #556 from runrevfraser/feature-rejig-prebuilts

Feature rejig prebuilts