Release v0.3.4.

* The 0.3 series of `vplot` introduces a breaking change for matrix
formatting. Matrices are now returned such that large fragments are at
the top. This can be reverted using the `-i` flag to invert the matrix
to have small fragments at the top instead (pre-0.3 behavior).

* `-o` flag for writing to a file path.

* the `--multi` flag writes matrices for each region in the input bed
file. An optional prefix or ouput directory can be added using the `-o`
flag.

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "vplot"
-version = "0.3.3"
+version = "0.3.4"
 authors = ["Spencer Nystrom <nystromdev@gmail.com>"]
 edition = "2018"