VB6 bindings and dynload update w/ uc_context* and uc_free api,… (#715)

* msvc unicorn.def and dynload.c added new uc_context* and uc_free api, includes support for older dlls compiled with uc_context_free (can remove next binary release)

* vb6 bindings & x86 32bit sample class for unicorn

bindings/vb6/.gitattributes

@@ -0,0 +1,11 @@
+*.frm eol=crlf
+*.bas eol=crlf
+*.cls eol=crlf
+*.ctl eol=crlf
+*.vbp eol=crlf
+*.txt eol=crlf
+*.cpp eol=crlf
+*.tli eol=crlf
+*.tlh eol=crlf
+*.vcproj eol=crlf
+*.sln eol=crlf