General cleanup

* sorted sections alphabetically
* used the same format (with a hyphen) everywhere
* removed link to an article, since that's not a project
* other small fixes (shortened overlong descriptions, added missing URL, more specific URL, removed license from descriptions, …)
Added Roslyn and F#

Roslyn and F# are both high profile open-source projects targeted at .Net developers. I don't see any reason why they should be omitted from this list.
Added log4net
Added ComparerExtensions

I think that ComparerExtensions is very useful whenever you need to create IComparer, so it should be included in this list.
Merge pull request #151 from svick/patch-1

General cleanup
Merge branch 'patch-2' of https://github.com/svick/dotnet into svick-patch-2

Conflicts:
	dotnet-developer-projects.md
Merge branch 'svick-patch-2'
Merge pull request #153 from svick/patch-3

Added log4net
Merge pull request #154 from svick/patch-4

Added ComparerExtensions
Merge remote-tracking branch 'upstream/master'