load default compilers before user defined compilers

[stathis-alexander]

Motivation

Currently, the tapioca default compilers load after the user defined compilers. This makes it impossible to extend or monkey patch a default compiler without monkey patching the load order in an initializer. See here for a comment concerning this behavior.

This PR switches the load order of default compilers to go before the user defined compilers. This allows users to extend the default compilers or monkey patch custom behavior with compilers of their own.