merge master
remove old parseRuleProperty() method
resubmit lost changes: better exception handling
add experimental Tree_NameValue
disable experimental Tree_NameValue
fix regression when parseBlock returns empty array
change exception type
use Tree_NameValue, organize parseImport
clean up parseCombinator
add Less_Tree::ReferencedArray()
remove redundant checks in PrepareRuleset
clean up Variable->compile()
check for NameValue in _removeDuplicateRules
correct typecheck in _removeDuplicateRules
clean up test interface
fix mixins-interpolated regression
archive lessjs 1.5 fixtures
make less.js 1.6 tests defaults
clarify test results
Merge remote-tracking branch 'origin/1.6' into 1.6

Conflicts:
	lib/Less/Exception/Compiler.php
	lib/Less/Parser.php
	lib/Less/Tree/Mixin/Call.php