Add updateApplicationSetting method

Added an updateApplicationSetting method that will allow you to update the newer applicationSettings in addition to just appSettings.
msbuild /noconlog
Merge pull request #463 from ctaggart/noconlog

msbuild /noconlog
Merge pull request #455 from bentayloruk/new-cli

New (backwards compat) CLI for FAKE that includes FSI cmd args passing
Merge pull request #462 from ssteward54/patch-1

Add updateApplicationSetting method
Bump version to 2.18.0-alpha1
Bump version to 2.18.0-alpha2
clean up to Roundhouse docs and messages
Merge pull request #464 from ChrisMissal/docs-fixes

clean up to Roundhouse docs and messages
Try to use F# 3.1 for Travis build - fixing #459
Revert "Try to use F# 3.1 for Travis build - fixing #459"

This reverts commit 28f094d485ecd0908bd62b88941061b24233bddb.
Fix issue where new CLI treated target=Clean as the positional target name.  Now reject positional argument containing =.  FAKE build.cmd example works and falls back to old CLI as expected.
Merge remote-tracking branch 'upstream/master' into new-cli