Summary:
Update fbcode_config.sh so that It try to use the latest version for dependencies that we are using, after updating the code these libraries where updated
```
Snappy: 1.0.3 => 1.1.3
GFLAGS: 1.6 => 2.1.1
JEMALLOC: 3.6.0 => 4.0.3
```
I have also updated clang from 3.7 to 3.7.1
```
Clang 3.7 => 3.7.1
```
Another change is that we use the same tp2 directory as fbcode, so we dont need to keep changing commit hash every time we need to change a version of a compiler or a library
Test Plan:
make check -j64
USE_CLANG=1 make check -j64
DISABLE_JEMALLOC=1 OPT=-g make all valgrind_check -j32 (make sure it's running)
Reviewers: yhchiang, anthony, rven, kradhakrishnan, andrewkr, sdong
Reviewed By: sdong
Subscribers: dhruba
Differential Revision: https://reviews.facebook.net/D53037
