Fixed a bug in the processing of HTTP response headers

Response header values with leading or trailing whitespace were parsed incorrectly, even though the HTTP standard specifies that such whitespace should be ignored (http://www.ietf.org/rfc/rfc2616.txt - Section 4.2).
This change trims said whitespace from all HTTP reponse header values.
[cs] don't add Runtime.toString call for string expressions
[cs] get rid of most "untyped __cs__" calls, use proper code generation instead
Merge pull request #2525 from agersant/development

Fixed a bug in the processing of HTTP response headers
[cpp] Do not eliminate 'never' accessors unless they are also external
allow having multiple types in the Array module
do not add non-core-type abstracts to swc dependencies (see #2590)
use proper class for array iterator on C#
fix Lambda.find documentation
also use iterator class on java
Merge pull request #2594 from nadako/cs_array_iter

use class for array iterator on c#
Split haxe.Json into Parser/Printer, move platform-specific stuff into platform folders
Add documentation for haxe.Json functions.
temp fix for doc_gen issue with UInt
(As3) make private @:op functions public in output (closes #2596)
[cpp] Array.splice takes 'last', not 'len'
do not remap positions of self calling closures (closes #2025)
move @:enum implementation to compiler
[cpp] Some initial support for mysql/sqlite. Not very well tested yet.
ignore @:multiType errors during DCE (they might be caused by @:multiType function arguments)