[5.3] Update `can` middleware to new namespace

Add missing Mandrill secret keys in config.services

[5.3] Remove the Authenticate middleware

[5.3] Make the Authenticate middleware throw an AuthenticationException

[5.3] Added the new bindings middleware

[5.2] Get guest middleware using guestMiddleware() method in ResetsPasswords

Applied fixes from StyleCI

[5.3] Add "sslmode" setting for PostgreSQL connection

The commit https://github.com/laravel/framework/commit/586bffa1d758e09114821b694b5e800cc9bbfb5f added support for sslmode in PostgresConnector.php and sslmode has been around since postgres version 9.1 (2011). 

This change makes it possible to specify sslmode from the config file.

Also serves as documentation to other developers so they don't have to
dive deep into the code to figure out that it's posible to set this option.

The posible values for sslmode are:
    disable, allow, prefer, require, verify-ca, verify-full

The default value is "prefer".

http://www.postgresql.org/docs/9.5/static/libpq-ssl.html#LIBPQ-SSL-PROTECTION

Add language line for image dimensions validation rule

[5.3] Enabled MySQL "strict" mode by default

Merge branch 'feature/session-store-config' of https://github.com/tomcastleman/laravel into tomcastleman-feature/session-store-config

Use Bootstrap 3.3

Unless there is a reason why not?

[5.3] Add config for new Memcached features

Adds config for persistent connections, SASL authentication, and custom options

guestMiddleware() defined on ResetsPasswords trait

This change is required to fix issue #13383

Depends on pull request laravel/framework#13384