Update README.md
1.7.3 release
Update bower for 1.7.3
Adding handling for upper case drive letter in Windows

The check fails when the path starts with a Windows letter drive that’s
upper case, causing the path to then include the currentDirectory.
This fails when a rootPath is specified along with an import statements
like:

@import url("brackets_colors.less");
Fix ordering of @import and @charset rules #1954 #2013

The genCss method of ruleset.js splits child nodes into two groups:
* rules,
* rulesets.

Rules are always printed first and have special handling for last rule.
Rulesets are always printed second. Wrong ordering was caused by the
condition that determined what is rule and what is ruleset.

Issue #2013: The condition made no difference between @charset and @page,
because both are compiled into tree.Directive nodes. I added isRulesetLike
method to the tree.Directive to differentiate between them.

Issue #1954: The condition treated all tree.Anonymous types as rules and
caused them to float up. That is incorrect, because `@import (inline)` is
compiled into tree.Anonymous too, but should be treated as ruleset and
stay where it is.
Source map changed together with import inline ordering
Removing useless comments.
Merge https://github.com/less/less.js into misleading-error-message-2069

Conflicts:
	README.md
Raise error in case of an empty selector inside :extend.
Merge https://github.com/less/less.js into rhino

Conflicts:
	README.md
Properties merging should work also inside directives #2035

Fixes issue #2035 - property merge inside @font-face. The _mergeRules function is now called also for directives with rules. It used to be called only for rulesets.

I had to turn off jasmine tests for merge.less, because it was replacing all urls by their assumed full paths. For example, the url(something.eot) was changed into url(http://localhost:8081/test/less/something.eot). The result did not matched with expected css and failed.

Note: I'm not sure why values order in source map changed. It does not seem to be caused by my change, it was failing before I made them.
Putting readme.md into its original state. Also, travis failed with weird
message and I want to see what it will do this time.

Previous travis error:
>> PhantomJS has crashed. Please read the crash reporting guide at
>> https://github.com/ariya/phantomjs/wiki/Crash-Reporting and file a bug
>> report at https://github.com/ariya/phantomjs/issues/new with the crash
>> dump file attached: /tmp/7685d81d-94f5-1db7-12c9006e-72f80442.dmp 0 [
>> 'PhantomJS has crashed. Please read the crash reporting guide at
>> https://github.com/ariya/phantomjs/wiki/Crash-Reporting and file a bug
>> report at https://github.com/ariya/phantomjs/issues/new with the crash
>> dump file attached: /tmp/7685d81d-94f5-1db7-12c9006e-72f80442.dmp' ]
Merge pull request #2117 from SomMeri/import-charset-ordering-2013-1954

Fix ordering of @import and @charset rules #1954 #2013
Merge https://github.com/less/less.js into misleading-error-message-2069

Conflicts:
	test/sourcemaps/basic.json
Merge https://github.com/less/less.js into font-face-property-merge-2-2035

Conflicts:
	test/sourcemaps/basic.json
Moved @font-face property merge test into urls.less and re-enabled
merge.less in jasmine tests.
Merge https://github.com/less/less.js into rhino
Merge pull request #2120 from SomMeri/misleading-error-message-2069

Misleading error message 2069
Merge pull request #2121 from SomMeri/font-face-property-merge-2-2035

Properties merging should work also inside directives #2035
Found race condition that caused file not to be skipped in importOnce, leading to random exceptions. Fixes #1931