#57 Support angle brackets for include name

[Zenju]

Hi,

currently (wxFormbuilder 3.4.0 beta) it's not possible to use angle brackets as the include name for the header of a custom class.

E.g.

In the object properties of some GUI control in wxFB the header of the subclass is set to <lib/header.h>. Now in the code that wxFB generates this will be incorrectly resolved to #include "<lib/header.h>". Note that both angle brackets and quotation marks are present in the include leading to a compilation error.