new buildsolution validation message
move language to core
move tests into core
rename folders
add languages to core project
rename language
rename test model
fix solution file picker for relative paths
fix path handling in build validation
add editor for build validation language
testcase working for mpsutil
Merge branch 'build-validation'

Conflicts:
	code/languages/com.mbeddr.build/solutions/com.mbeddr.mpsutil.dev.build/models/com/mbeddr/mpsutil/dev/build.mps
remove unused dependency on buildvalidation
remove old typesystem rules from buildutil