make test more lax so it accepts either 0px 0px or 0% 0% as valid default values for background-position
only try to normalize the units to px on IE if it's not directly set on the style attribute
Merge branch 'gonchuki-fix_getStyle_IE_units' closes #2417
Merge pull request #2556 from gonchuki/fix_background_position_test

make test more lax so it accepts either 0px 0px or 0% 0% as valid defaul...
Adding parenthesis around condition to fix IE8, after 912a2360

https://github.com/mootools/mootools-core/commit/912a23600d64d9c8030a58c700ac6617e09475ca#commitcomment-5228993
remove feature check for Presto
Merge pull request #2557 from gonchuki/removePrestoComputedStyleCheck

remove feature check for Presto
Fixing typo in YAML header for Fx.Morph Specs.
Fixes #2378

Add note to Element.empty that GC is not used.
Fixes #2515

Doc changes to Request.md to correctly reflect argument `async` in the options of Request.
Fixing Browser.ie for new IE11 UA string.
Browser: Use 'rv:' field of UA for modern IE version.

References:

- #2534
- #2539
Browser: For modern IE (that is IE > 10), set Browser.modernie, for others we keep Browser.ie.

Rationale:

The primary use of `Browser.ie` is activating legacy code, such legacy
code is no longer required in modern IE (and may not even work anymore).
Keeping `Browser.ie == true` for modern IE would do more harm than good,
even though it's technically correct. Since everyone seems to agree UA
sniffing should be phased out, this technical incorrectness shouldn't
cause any problems. Moreover, `Browser.ie11` will still work and
`Browser.name` will still equal "ie".

References:

- #2534
- #2539
merge: IE11 UA string detection (Browser.modernie). (#2534, #2539)

Based on work by @dez87 in #2539.
Created task to build MooTools

`grunt build:all` is working.
`grunt build:nocompat` is having trouble removing the `.*compat` blocks.
Fixed nocompat build.
Using grunt-mootools-packager
merged 1.x specs into a single directory. removed unnecessary files.
Forgot to merge Native -> Types
Fixing YAML headers.