Updating GA.
Adding new flexible_attrs class attribute.

This will hold (in order) the attributes that can be used as object references
for easy lookups.
Adding Flexible object method (test).
Fixing UA.
flexible -> resolvable -- better name
Add optional account store for password reset

When creating a password reset token the user can now specify an account
store that hold the desired account. If no account store is specified
the Backend uses the default account store to look for the account.

This is useful if one has multiple account store for an application
that hold the same email address.
Merge pull request #103 from denibertovic/develop

Add optional account store for password reset
Updating changelog to include docs on password reset changes.
Removing unnecessary whitespace.
Cleaning up our Account class.
Adding in tests around resolve_group helper for accounts.
Removing Account.resolvable_attrs.

This isn't being used since it's basically impossible to make things work this
way :()
Cleaning up Account._resolve_group.

It now provides an AMAZINGLY AWESOME interface for developers. You can get a
group in any way possible =)
Removing Group.resolvable_attrs.

Not used any longer.
Changing param name.
Cleaning up some logic.
Adding tests for our improve Group._resolve_account stuff.
Making Group._resolve_account work with custom search criteria =)
Cleaning up naming.
Spacing.