Merge pull request #164 from gladhorn/docs

Add overview documentation
Remove "users" example as not that useful
Update changelog.
Merge pull request #165 from nierob/smallImprovements

Small improvements
Some polishing on the examples and updated screenshots
Merge pull request #166 from jbache/master

Updated doc screenshots and polished examples
Fix the build on Windows

Do not use ENGINIOCLIENT_EXPORT in plugin code
since it messes up the build on Windows.
Add missing export for EnginioFakeReply since
the symbol is needed by the plugin.
Fix the out-of-the-box experience for QtQuick examples on Windows

On Windows the binaries are produced into the release/debug subfolder
so we need to adjust the QML import path additionally.
Also remove extra main.cpp and use the shared one with the todos example.
Merge pull request #167 from bbandix/windowsFixes

Windows fixes
Add last missing error message when a path is constructed.
Avoid creating a temporary string.
Merge pull request #168 from nierob/smallImprovements

Small improvements
Add proper error handling when uploading a file
Simplify logic in UploadProgressFunctor
Fix a memory leak.

We need to collect connections objects from time to time if not memory
usage will grow infinitely.
Use a macro list to reduce code duplication in EnginioString class.
Make ImageModel not editable.

By default the view is showing a line edit, which looks strange and
images are not editable anyway.
Use config file for examples

The examples will try to use a file named
EnginioExamples.conf
and if it doesn't find any, it uses the system config (.config/com.digia/EnginioExamples.conf)

The config must look like this:

[image-gallery]
backendId=@ByteArray(abcdef...)
backendSecret=@ByteArray(Aabcdef...)

[todo]
backendId=@ByteArray(123abcdef...)
backendSecret=@ByteArray(1234abcdef...)

The approach can later be extended to even create a new backend for the example.
Merge pull request #169 from nierob/smallImprovements

Add proper error handling when uploading a file
Merge pull request #170 from gladhorn/exampleconfig

Use config file for examples