Make `DefaultsError` a real `Error` object
Fix error in the output minifying `Function("return this")()`
minor optimization

unlikely to help in hand-written code:

    (something() ? foo : bar) == foo  ==>  something()
add `clean_getters` compressor option (default `false`)

allows one to specify if `foo.bar` is considered to have side effects.
Only allow identifier start characters at the beginning of identifiers.

Without this fix, the following source:

   x = {"\u200c": 42};

would incorrectly be converted into a quoteless key. But while \u200c is allowed
to be in identifiers, it cannot be at the beginning, as per ES5.

(For example, the SockJS client library doesn't work under uglify starting with
d9ad3c7c.)
Merge pull request #308 from meteor/fix-unicode-keys

Only allow identifier start characters at the beginning of identifiers.
Rename clean_getters to pure_getters; add pure_funcs.
Don't drop_unused before compression.

Fix #280, #282
wrap up
`arguments` outside of a function is an ordinary variable.

Fix #501
v2.4.1
Revert #3a81f60 for now

(with it some tests break and it can generate invalid output, see issue #44)
Add an exit code to the test suite

By adding the exit code 1 (or any other non-zero exit code) `npm test`
will know the tests didn't perform correctly. This way it's easier to
know if pull requests are good or bad.
Merge pull request #322 from rvanvelzen/test-exit-code-1

Add an exit code to the test suite
Fix #280

The `init` of the `ForStatement` is not a `BlockStatement` before it was
descended. The descend has to happen first, and *then* the actual
checks.
Merge pull request #323 from rvanvelzen/undefined-drop-vars-fix

Fix #280
Fix #269

Shorten most primitives where possible. Also optimize some edge cases.
Merge pull request #325 from rvanvelzen/fix-269

Fix #269
Add a unit test for issue-126 

Add a unit test to test to test for aggressive parenthesis removal that causes functional changes.
Fix RHS concat (raised in #330)

When attempting to concat the left-side of the rhs, make sure the rhs is
a string.