created less.log_level setting

This will control the amount of logging in the javascript console that
less will do while parsing.

Options are:
    2 - Information and errors
    1 - Errors
    0 - None

Defaults to 2
added semi-colons to end of lines where missing
Merge branch '1.5.0-wip' of https://github.com/gitaarik/less.js into 1.5.0-wip

Conflicts:
	lib/less/browser.js
Use the log method for logging errors and turn the number into an
enumeration.