fix win32 port
And also revert the lazily load pthread.
It seems that luajit cannot resolve symbols recursively from dynamically linked
libraries like in the linux. So that we do need to get platform specific pthread
libraries in different platforms. So does the mupdf library.
make test only if compilation succeeded
fix Travis building error of 'no nasm (Netwide Assembler) found'
fix android build
Merge pull request #4 from chrox/master

fix win32 port