Uproot

PR 380, which fixes 367.

PR 372, fixing issue 371: reading `std::string` and `std::vector` of numbers in unsplit objects.

Fixed issue 345 (PR 368)

Cleaned up Histogram writing code. (PR 370)

Removed flushing mechanism. (PR 369)

Issue 365 and PR 366.

Raise `NotImplementedError`s for known issues (that we plan to fix in the future). (PR 353)

Fixes issue 352. (PR 357) - A crucial fix to uproot's serialization of ROOT data.

Updated documentation to reflect ability to write TTrees. (PR 362)

Fixed the following:

* PR 346 (issue 345): Changes the flushsize default at the tree level to 30 MB from 30 KB.
* PR 350 (issue 306): Better error message when attempting to open multiple branches with `Tree.array`, `Tree.lazyarray`, or `uproot.lazyarray` (all the singular versions of methods with a plural alternative).
* Issues 349 and 347: Added text to README.rst and tutorial.ipynb about flattening jagged arrays before histogramming and about the existence of TChain alternatives.
* PR 351 (issue 348): Support RangeIndex in Pandas `<0.25.0` and `>=0.25.0` with `hasattr` checks.