Started 4.2.1 development.

Conflicts:
	build.sh
Updated submodules' HEADs.
Change target for build script. Add editor version and -all. Ex. (/build/full -> /build/4.2.1/full-all).
Updated submodules' HEADs.
Get editor version using ./build.sh -v.
Reverted SCAYT and WSC versions so they correspond to 4.2.
Add suffix to version name (4.2.1 -> 4.2.1 DEV).
Updated submodules' HEADs.
Merge remote-tracking branch 'upstream/release/4.2.x' into release/4.2.x.haiku

Conflicts:
	ckeditor