FIXES ISSUE #1453: let ModifyVar change numerical variables
Use parent ids instead of recursive calls to inInheritanceChain()
Set object id and initiate parent_ids array
fix whitespace
Fix the return code when asking for help/options. Fixes #1664
Merge branch 'ModifyVars_Numerical_Vars' of https://github.com/MSamman/less.js

Conflicts:
	lib/less/browser.js
* functions.js: (minor) reworking to clean-up initialization of "externally" defined functions (math, blending, `default`).

* `default` function "front-end" reworked for a bit higher-level control from its "back-end" code (e.g. tree.mixin.eval).
`default` function: added error when used with css-guards. updated tests.
Removed redundant code from tree.Selector.match()
Merge pull request #1757 from seven-phases-max/tree-functions-cleanup

Tree functions cleanup + CSS Guards `default` error.
Merge pull request #1758 from seven-phases-max/master

Removed redundant code from tree.Selector.match()
Merge branch 'patch-2' of https://github.com/oyejorge/less.js
Merge branch 'master' of https://github.com/cloudhead/less.js
add banner option. Fixes #1735