gmcs uses 2.0 profile libraries, so make MonoMac.dll throws System.Threading.Tasks namespace missing errors. Fix by using dmcs, which uses 4.0 profile libraries.
Add bindings for DomHtmlTextAreaElement to fix https://bugzilla.xamarin.com/show_bug.cgi?id=11693
Remove MCS change for pull request.
Merge pull request #109 from bjcy/dombindings

Add DomHtmlTextAreaElement bindings