expect to have static, hosted, packaged modes

[gasolin]

followup of webapplate/webapplate#15

After basic generator is landed, the requirement is more clear now.
I'd plan to have 3 modes for generated template, which mapping to 3 grunt commands:

static: not install express related script (no views/, server.js)

tasks:

• remove unnecessary grunt config
• remove unnecessary package.json dependency
• ? add https://github.com/gruntjs/grunt-contrib-connect as static server

pack: inherit from static, but without server (no appcache)

tasks:

• remove unnecessary grunt config
• remove unnecessary package.json dependency

host: (not in current scope)

tasks:
add grunt host command
webapplate/webapplate#69

[gasolin]

Since the scope is wide, I think we could focus on make pack mode works well during TSOC.

@littleq0903 @snowmantw any thought?