Removed dependency on node-gyp
Removed dependency on node-gyp

Use the one bundled with npm. Also, npm itself compiles it on install when if finds a bindings.gyp file
jprichardson/node-kexec,foysavas/node-kexec,foysavas/node-kexec,jprichardson/node-kexec,jprichardson/node-kexec,foysavas/node-kexec,jakubskopal/node-execpe,jakubskopal/node-execpe,jakubskopal/node-execpe