checkcommit: don't check out the original commit

checkcommit depended on the output of git branch which it should never
have done since it isn't stable. Looking at the git-prompt.sh code from
git-contrib, getting back to the original state in the way we wanted
would be really hard, so just skip it. checkcommit was always supposed
to be a low-level abstraction of the build process anyway.
Set a timeout for MessageTransportTest.messageHandlerTest
build.xml: Remove dependency on missing target
checkstyle: remove DoubleCheckedLocking test

The DoubleCheckedLocking test has been removed from newer versions of
checkstyle, so remove it to avoid breaking the build.
Should end with ".freemail" not "freemail"
Merge remote-tracking branch 'zidel/infrastructure_fixes'
Fix checkstyle warnings
Eclipse formatter: indent with tabs, not spaces
Revert "Fix possible NPE from fcabf976502d2686c4f0c29d046d063d57494ba7"

This reverts commit 62b15bd19af1895dc627a9269b135e7d149ce213. The values
are checked a few lines above, so they can't be null at this point
Remove unused imports
Only allow correct From address through header filter
Add tests for various From header scenarios
Fix identation/whitespace
Clean up what is defined in build.properties and build.xml

build.properties now defines default values for all the variables that
it would make sense to vary locally, and build.xml defines those that
people should probably not mess with.
Test filtering of multiline header with tabs
Test filtering of unknown header
Fix Changelog.
Merge remote-tracking branch 'zidel/from_header_fix'
Update Changelog for merge
Merge remote-tracking branch 'zidel/various_patches'

Conflicts:
	test/org/freenetproject/freemail/MailHeaderFilterTest.java