added handling for complex inline values

meaning inline values containing commas (see tests for examples)

this is note being used anywhere yet
improved handling of complex inline values

now supports both with and without whitespace after delimiter - except
for one special case (cf. tests)
renamed internal variables, updated/clarified comments
added support for labels with commas
improved encapsulation of inline-value handling

by using the new helpers introduced for complex inline values
Merge branch 'master' into comma-separated-labels

Conflicts:
	app/models/collection/base.rb
	app/models/concept/base.rb
Revert "improved encapsulation of inline-value handling"

breaks a lot of tests because it is applied to more than just labels

This reverts commit 428600462fe87c497e019142b0224b6cd77c5b5f.
ensured inline-value handling can cope with empty strings
restored appropriate helper for inline-label generation

this was erroneously removed with the previous revert
(2740ce33414b8543496eb06245c3e6e24145ff28)
avoid using camelized constant names
fixed case of InlineDataHelper constants
fixed erroneous block ending
Merge branch 'master' into comma-separated-labels