Adding word count in view toolbar

[Daksh]

For a GCI 2015 task: https://codein.withgoogle.com/dashboard/task-instances/5210754919694336/

[i5o]

This is enough for the task.

Before we merge we should look another solution for replace the GObject.timeout_add, I tested with idle_add, and didn't worked

[samdroid-apps]

Please use _word...

[samdroid-apps]

Looks good, here are my overall comments:

• does the regex work with languages other than English? Charectersets other than English?
• maybe move the label into the activity toolbar (icon: coloured write icon) - there is lots of metadata there already
• only update it when the toolbar is open (and therefore when the label is visible)
• add a description explaining WHY you used regex rather than an abiword function - explain that abi doesn't expose this apoi

[samdroid-apps]

Actually have a look at abi's algorithm, it looks very efficient and it also deals with other languages. Maybe you could use it?

https://github.com/AbiWord/abiword/blob/c64130a42934fc5618f56c5ab8d028b52e41db43/plugins/grammar/xp/AbiGrammarUtil.cpp#L64