Implemented most methods of wxFileDialog

[mrcdk]

Methods that aren't implemented:

• getExtraControl() http://docs.wxwidgets.org/trunk/classwx_file_dialog.html#a0b6e2bfdb5997e74c99fcf6d3249a798
• setExtraControlCreator() http://docs.wxwidgets.org/trunk/classwx_file_dialog.html#aa312b8ae7961060c3116457c6334b527
• getFilenames() and getPaths() http://docs.wxwidgets.org/trunk/classwx_file_dialog.html#a282cf846facc9eae4682c43627229e9c I'm not sure how to do that.

Also, filterIndex seems to throw an error if there are no wildcards.

Only tested on a Ubuntu 16.04 using latest dev Haxe and hxcpp.

Should be enough for issue #29

[ianharrigan]

Great! Any chance you can fix the checkstyle? Line is 226 chars long, which is 1 to many... Might make sense to break it up / simplify it anyway as even 225 is pretty long. (Although i get that its just a log line)

[ianharrigan]

Also you can ignore appveyor checks... they arent setup so will always fail (im removed it from the project for now)

[ibilon]

Travis succeeded and code looks good, thanks for the contribution!

[mrcdk]

okay, done @ianharrigan

[ianharrigan]

Perfect... thanks @mrcdk