modernize build: drop Scala 2.9.3 & 2.11 modules dependency
remove deprecated 'typelevel' module
nuke deprecated MetricSpace and BKTree
nuke deprecated Length, Each and Index
remove deprecated functions from core
remove deprecated functions from effect
remove some remnants of 2.9
replace use of (Class)Manifest by ClassTag
fix remaining deprecation warnings
fix more deprecation warnings
nuke more deprecated items
remove deprecated 'xml' module
simplify compiler settings
drop Java 6 support
remove deprecated scalaz.concurrent.Promise

Deprecation happened in 1677080 (after the fork point of 7.2.x), which
is why it appears to be removed "out of the blue" here.
Merge pull request #780 from larsrh/topic/next

Modernize for 7.2.x