Now depends on awkward 0.7.0+ and uproot-methods 0.3.0+.
Strict dependency on the lz4 library was removed. It was difficult for some users to install and not needed for all ROOT files. If users encounter lz4-compressed or lzma-compressed ROOT files and they don't have these libraries, a message with copy-pasteable pip and conda installation commands are provided. This resolves the confusion raised in 186 and avoids 192 if possible.
The HTTPSource doesn't rely on `"content-length"` being correct if the total size is not larger than the chunk. This works around a bug where XRootD servers in HTTP mode were giving the wrong value. Issue 190.
Now `help(uproot)` returns a useful cheat-sheet. Issue 191.
All TTree access to Numpy is done through `awkward.util.numpy`, preparing for a test in which we swap Numpy for CuPy and read ROOT data directly into GPUs.