* Add from_file_parallel()
* Improve performance of operations on sparse arrays.
  - lil_matrix slicing is too slow. Use csr_matrix instead. Column
    slicing of csr_matrix is slower than row slicing, but it's still
    much faster than column slicing of lil_matrix.
  - csr_matrix can't support fancing indexing like csr[slicing] = update.
    Use hstack, vstack to implement to simulate fancing indexing. It's
    faster but can't support slicing with step is not 1. This should
    be enough for Spartan.
Add the missing csr_update
Comment and typo fixed.
Merge branch 'master' into from_file_parallel
Temporary version. But there is a memory leakage issue.
Some optimization to speed up and reduce memory usage.
Merge branch 'master' into from_file_parallel

Conflicts:
	spartan/expr/write_array.py
Test refine
From file sparse version
use broadcast send in rpc
Typo
Add accidently deleted files
Comment
seperate send and send_raw functions.
still make rpc_id of broadcast in seperate range
use _rpc_id_generator for all clients and broadcast messages
use send_raw instead of call_raw in forall function.
Merge pull request #95 from EasonLiao/rpc_broadcast

use broadcast send in rpc
A few simple performance optimizations.

The Traits library overrides __reduce__ex__; if we override it
ourselves we can make things a bit faster.

Reduce logging.  Python logging is terribly slow.
Merge pull request #97 from spartan-array/perf-tweaks

A few simple performance optimizations.