### 0.3.1.0
- Do not throw the error if */dev/tty* cannot be open. Note that Neovim loads
the syntax engine without *tty* emulation just fine. This allows using Neovim
as *VIMHL_BACKEND* in environments where */dev/tty* is unavailable.
### 0.3.0.0
- Support for packages *base* < *4.8* and *pandoc-types* < *1.20* was
dropped.
- If output format is *gfm*, the code block gets translated to a *RawBlock* in
*HTML* format with style adhered to code blocks in Github README pages.
- Use environment variable *VIMRC_PANDOC* to point to the custom vim
configuration.
- Cabal flag *debug* was removed.
### 0.2.0.1
- Removed dependency on package *safe*.
### 0.2.0.0
- Removed dependency on packages *regex-compat* and *cond*.
### 0.1.4.0
- Use environment variable *VIMHL_BACKEND* to choose between vim flavors.
### 0.1.3.0
- Updated after Pandoc *2.8* and the *String-to-Text* migration.
### 0.1.2.4
- Removed *shebang* line as it may lead to compilation failures.
### 0.1.2.3
- Added support for older GHC *7.8*.
### 0.1.2.2
- Added Cabal flag *debug* (off by default) for printing how vim runs to
*stderr*.
### 0.1.2.0
- Better treatment of handles of temporary files.
- Using *WriteMode* for vim process *std_in* prevents vim from getting
unresponsive on *Ctrl-C* interrupts while still doing well its tasks.
- Using */dev/null* for vim process *std_out*.
- Exit program as soon as vim fails.