Application boot refactoring

Hello @dpup, 

Please review the following commits I made in branch 'vinny-refactorings'.

12f35b8424b0a0af543c4d9a09f80abebc589f6c (2013-06-11 21:04:58 -0700)
Add deprecation warning for template engine registration #jankAndDrank

643d06c43d2a12f9a399089acbab1d5fb0174050 (2013-06-11 21:04:56 -0700)
FileLoader's appDirs is public for now #jankAndDrank

4e6ca46a23c467aae7bc63e0608f4d155479e982 (2013-06-11 21:04:54 -0700)
Restoring argv and CacheHelper for retro compatibility purposes #jankAndDrank

1e1cfb164881d416611dcb4b739ddcc3c81ef0ae (2013-06-11 21:04:51 -0700)
Extracting File/Class loading logic into separate classes #jankAndDrank

6d30fef6ea1313218dfa702b941ec2a7fd1deec7 (2013-06-11 21:04:49 -0700)
Move Pathmatcher test to unit path #jankAndDrank

b184ea0c086634db970d8fdfb61ba7a31b031642 (2013-06-11 21:04:47 -0700)
Moving fileExists to fsutils #jankAndDrank

dc43a0c225feedec6500a3392d116307cb5b8443 (2013-06-11 21:04:45 -0700)
Removing unused dependencies #jankAndDrank

dbe0e101cb8b90630cf4603901139ddab27942dd (2013-06-11 21:04:42 -0700)
Removing unused minify function #jankAndDrank

5e05d2288545c5b2e70d44202afd28ee34fde64b (2013-06-11 21:04:40 -0700)
Removing unsupported argv #jankAndDrank

788f994765fc1be5848868e177941981fabfb428 (2013-06-11 21:04:35 -0700)
Moving middlewares to app.boot #jankAndDrank

1161090632d0549ad2fd1140808e3e6776670072 (2013-06-11 21:04:30 -0700)
Adding querystring parser as middleware #jankAndDrank

5caf80d021789f79abd22e5e195dd3e5d0ac9f89 (2013-06-11 21:04:27 -0700)
app.configure is not necessary #jankAndDrank 

R=@dpup