package: remove the 'preinstall' and 'install' scripts
package: remove the 'preinstall' and 'install' scripts

This way, older versions of npm (that don't bundle node-gyp) will
automatically use node-waf to compile (seeing the wscript file),
but newer versions of npm (that do bundle node-gyp) will use node-gyp
to compiled because it sees the binding.gyp file.

sergeche/libxmljs,improvisio-software/libxmljs,libxmljs/libxmljs,sergeche/libxmljs,libxmljs/libxmljs,polotek/libxmljs,CodeFridge/libxmljs_mem,hildjj/libxmljs,gagern/libxmljs,improvisio-software/libxmljs,CodeFridge/libxmljs_mem,rchipka/libxmljs,polotek/libxmljs,rc0x03/libxmljs,Konsus/libxml,rchipka/libxmljs,Visya/libxmljs,hildjj/libxmljs,rc0x03/libxmljs,Visya/libxmljs,gagern/libxmljs,libxmljs/libxmljs,improvisio-software/libxmljs,sergeche/libxmljs,rchipka/libxmljs,rc0x03/libxmljs,Konsus/libxml,CodeFridge/libxmljs_mem,gagern/libxmljs,Konsus/libxml,Visya/libxmljs,hildjj/libxmljs,polotek/libxmljs