Minimize the scope of some string consts

Help prevent "duplicate symbol" linker errors when this code is included more than once in an app (because one or more libraries includes this code).
And...two more potentially duplicate symbols fixed
oops - fix typos
Allow project prefix for all public symbols
Seems to be a day for typos...
Added support for the iPhone 6 and 6 Plus for ACME and ACME Browser

This PR should resolve #139.

**ACME**

**Before:**

![](https://www.evernote.com/shard/s340/sh/60979147-36a2-443b-b476-47b022e4b4f8/b39cf0f72bcc1bee5bc5b0107772abd7/deep/0/IMG_0185.png)

**After:**

![](https://www.evernote.com/shard/s340/sh/241c1ed4-790a-46ff-ae35-b3f503741386/63ee026aa4d327a57dbbe04c37c8fd8b/deep/0/IMG_0186.png)

**ACME Browser**

**Before:**

![](https://www.evernote.com/shard/s340/sh/0c18b0c1-2664-413d-bf7f-f40c15b2606a/4b3445d5971c7f80f2652191e1866cb4/deep/0/IMG_0188.png)

**After:**

![](https://www.evernote.com/shard/s340/sh/3f2f2b98-4c4c-48f2-86b8-64e443985e6b/60776fbf860336199487bde283f3c71c/deep/0/IMG_0187.png)
Updated images.xcassets for ACME
Use #defines to prevent duplicate symbol conflicts
tidy up a bit
Merge pull request #137 from dgoldman-ebay/master

Minimize the scope of some string consts
Merge pull request #140 from AgileBits/add-support-for-iphone-6-and-6-plus-for-acme-and-acme-browser

Added support for the iPhone 6 and 6 Plus for ACME and ACME Browser
Merge branch 'master' into add-low-level-api
Added support for iPhone 6 and 6 Plus to Low Level API demo apps too.