#144 wxStEdit Build error

[smitchell]

Using SVN rev. 3015
wxCheckBox not defined in context.
Build env. MinGW 4.6.1, wx2.9.3 monolithic DLL, win7-x64
Patch file attached

[smitchell]

added forward definition

[John Labenski]

Thanks for the patch, applied to SVN head.