Working on faster serialization.
Refine some test files.
  - Meaningful nameing for test cases.
  - Remove annoying messages of test_trace.py
  - test_fio_path can't pass on both single machine and clusters, comment it.
test_fio.py now select test directory by detecting it first
Merge remote-tracking branch 'upstream/master'
Missing default_rpc_timeout in the upstream/master
Merge pull request #43 from fegin/master

Refine some test files.
Add sparse arrays support in make_from_numpy().
* fix the bug in some test cases
Merge pull request #2 from MaggieQi/faster-serialization

Faster serialization
write_array.py code refinement
Merge pull request #45 from fegin/master

Add support for sparse arrays in make_from_numpy().
Make from_npy as an independent function.
* add test cases for serialization
Remove acidentally committed code.
Merge branch 'MaggieQi-master'

Conflicts:
	spartan/rpc/common.py
Rename from_npy to from_file
Make dot expr as an Expr
Make dot expr as an Expr
Merge pull request #47 from fegin/master

Make from_npy as an independent function.
Some performance tweaks for testing.

Assert.* methods take a `msg` argument, which is preformatted.  This
means that we end up taking the hit of formatting arrays/etc even
if the assert passes.  Change to formatting internally to avoid
this.

Formatting the expression stack seems to take longer than we'd like.
Capturing just the frame doesn't work for some reason, so make
it an optional flag.

Try to pretty print stacks a little bit.  Common regions of the
stacks should be removed as well at some point.