failed to install on win8.1

[ottomao]

It seems that anyproxy installation is failed on win8.1

Here is some log from a user's report

6870 error contextify@0.1.9 install: node-gyp rebuild
6870 error Exit status 1
6871 error Failed at the contextify@0.1.9 install script.

[ottomao]

一些三方模块的依赖被移到optionalDependencies里面去了，理论上不会再报这个错。

[ottomao]

移除了对 .anyproxy_home文件夹的强依赖，现在windows系统可以正常安装使用。