* [PASS] Refactor thread storage sync to a common visitor

* Fix the sync scope check behavior

* prefetch interface added

* prefetch python comments modified. prefetch info data structure maintained.

* start injecting prefetches. first step (domain touch) implemented.

* domain touch tested.

* Prefetch ir_mutator and ir_visitor dispatch registered.

* modify domain touched from passing a func_ref to passing a tensor

* modify domain touched from passing a func_ref to passing a tensor

* modify Tensor copy to Tensor ref

* temp commit for rebase

* debug info removed, typo fixed, ready to rebase

* prefetch flatten test add!

* roll back builtin functions to side effect functions

* lint error fixed!

* add cache line size to storage flatten argument

* forgot modifications add

* change code style to dmlc-like; get rid of can_prove, use manually compute instead

* python lint error fixed

* modify instrinsic name to pass tests

* [TEST] get rid of str(), replace them by accessing attributes

* change map to list comprehension

* redundant numpy import removed

* [REFACTOR] collections->container, RPC returns func, time_evaluator returns struct

* fix executor

* [CODEGEN/PASS] add restricted, alignment option

* fix lint

* Fix the alloca

* [PASS] StorageRewrite, reuse memory pass as in NNVM.

* fix issue

* [DOC] Initial doc system

* Migrate API

* Update docs

* [SCHEDULE] Add group, refactor thread bind api.

* fix doc

* fix g++-4.8

* More testscase

* Remove graph context from fix pt analysis

* [IterVar/REFACTOR] Add types to IterVar

* [ARITH/REFACTOR] Move IntSet to include

* [REFACTOR/OP] Move Op detail to seperate folder.

* fix test

[TEST/PYTHON] Add unittest folder, add a build pipeline. Rename Buffer.ptr to Buffer.data to be consistent with Array. (#29)

* [CODEGEN] Add LoweredFunc, MakeAPI and SplitHostDevice

* update halideir