Added client.use() so command can be added from modules
fix(dependency): remove lodash.merge dependency hell

Single lodash packages eats too much dependency ressources and downloads
for such a simple package like lodash.merge.

fixes #157
added node-coveralls and mocha-lcov-reporter for code coverage
added istanbul as local dev dependency
improved test handling
fixed npm script call
removed reporter arguments
fixed istanbul command, improved coverage script
improved 'use' test
removed mocha-lcov-reporter
replaced dependency badge with coverage badge
fix(waitFor): waitFor should not overwrite implicitWait globally

Before this fix, waitFor was setting implicitWait for the whole
session.

We now set it back to the default.

A better approach would be to set it back to what it was previously.

I do not need this atm.
fix(element strategy): name strategy collides with css selectors

before this commit, it was not possible to:
.click('[name="hello"] a div') because it fall into name strategy
instead of css selector strategy
chain each instance separately
Merge pull request #163 from camme/fix-157

fix(dependency): remove lodash.merge dependency hell
Merge pull request #168 from camme/fix-waitFor-command

fix(waitFor): waitFor should not overwrite implicitWait globally
Merge pull request #169 from camme/fix-find-element-strategy

fix(element strategy): fix find element strategy for name/css selector
Merge pull request #170 from camme/feature/oneQueuePerInstance

chain each instance separately
Merge pull request #164 from camme/code-coverage

added code coverage
removed 'behind an overlay' tests because they are featureless