Enable lexical binding

Fix a few bugs that turned up as a result.
Fix some whitespace.
Fix docstring in ebib-edit-field
ebib--set-modified: return MOD

It seems that set-buffer-modified-p now returns nil instead of its argument.
Use prefix argument instead of called-interactively-p
Fix indentation issues.
Fix typo in ebib--add-entry-stub.

Fixes issue #52.
Add parsebib.el to repo.
Do not use lexical-binding in ebib-filters.el

This messes up the macrolet `contains' in ebib--filters-run-filter.
Implent parsebib library.
Remove parsebib.el from repo.
Reverse b6db2b82ab07d290ebec1a4b9767faf4278b50a3

Since loading of a .bib file is handled differently, it is no longer
necessary to reverse the field values upon saving.
Implement local variable block.
Set bibtex-dialect buffer-locally, not globally.
Move parsebib dependency to ebib.el
Add `nil' to the completion options in ebib-set-dialect.

`nil' is needed to unset the dialect.
Update biblatex section of the manual.
Fix typos in keybindings for index buffer.
Read biblatex .bbl files.
Fix :group in ebib-window customisations