Better wording in the verified command help texts

Change-Id: I74b4a061bb8ae01600a8f74c5d12a2afcbc58329
Replace deprecated `gerrit approve` with `gerrit review`

The `approve` command is deprecated since Gerrit version 2.1.3.

Replace it with `review` throughout the code.

Change-Id: Iada958c16f630fb171459bc38214984e398c65a6
Fix indentation in help files

Indent with spaces rather than tabs.  Use correct indentation levels.

Change-Id: If97d4a2255e757cdbf9e72c8894e872fb99e6ab3
New option to check changes from Gerrit and trigger missed patchset created events.
Bug fix: Support to use silentMode with check missed patches property.
Refactored check missed patches property.

Fetches only once every needed project from Gerrit server.
Rename constants for better readability and consistency

The constants `PROTO` and `GERRIT_PROTO` are renamed to `SCHEME` and
`GERRIT_SCHEME`.  This makes the naming of all the provider constants
consistent with RFC3986 [1].

The `proto` field is replaced with `scheme`.  The methods to get and
set `proto` are deprecated and new methods to get/set `scheme` are
added.

JSON parsing is modified to use `proto` if it exists, or otherwise
use `scheme`.

[1] http://tools.ietf.org/html/rfc3986

Change-Id: I38890355daa5d614e6b43fd351b199ed4f9e83c1
Fix grammar in help descriptions of Gerrit provider fields

Change-Id: I7a44a842e32a6bcccc81b829abd6d1b1a7afeedb
Add missing event types in description of change events

Change-Id: Ie066e281c7c20a432616c0668d076e18254df25d
Fix minor typos in comments

Change-Id: Ia8b00bd0f8b6f981b6c35f9f1f28089f1ed2ec9a
Refactored Trigger missed patches property
TriggerMissedPatches class name changed to TriggerNotReviewedPatches
Bug fix: Triggers only selected unreviewed changes
Removed useless logs from check unreviewed patches property.
Non-reviewed patch support refactored.
Add new interface for handler

Now library user need to use GerritHandler directly to handle event.
It has possibility for user to call unnecessary method.

To avoid this, this patch provides new interface class to use
GerritHandler safely.

Also new connection event type is provided.
Implement Handler to GerritHandler

This patch implements Handler to GerritHandler.

Some methods are deprecated. And GerritHandler will not provide
connection status anymore.
Refactored non-reviewed patches property to implement a GerritListener.
Refactored Gerrit project list to use iterators.
Added GerritProjectList tests.