Revises types of code processors. Changes SINGLE_USE to
KEY_RELEASE. The only processor using it is `gocode`,
which is now to be run whenever a specific character
is entered by the user.

Signed-off-by: Jim Teeuwen <jimteeuwen@gmail.com>
Performs some code refactoring and properly filters out
key events targeted at processors with the KEY_RELEASE mode.

Signed-off-by: Jim Teeuwen <jimteeuwen@gmail.com>
* Refactors code.
* Removes need for `Gedit.View` parameter from `Process.run` calls.
* Implements parsing of JSON data coming from the `gocode` daemon.
* Fixes README and Makefile to add dependency on `json-glib-1.0`.

Signed-off-by: Jim Teeuwen <jimteeuwen@gmail.com>
Removes the use of `json-glib`. It is yielding linker
errors I can't seem to fix. Additionally, the output of
`gocode` is much easier to parse if it is requested in
`csv` format. We can simply split lines and have no use
for another external library.

Signed-off-by: Jim Teeuwen <jimteeuwen@gmail.com>