Improve names for functions and state variables

[JacobVanGeffen]

Inappropriately named functions/variables should be changed to follow these rules:

• Function names should reflect whether or not they update state (e.g. functions prefixed with check should not update state).
• Nouns should be used to describe getter functions.
• Verbs should be used to describe state-affecting functions.
• State variable names should describe the class of data that the variable pertains to (e.g. prefix or postfix with ip when a variable only describes in-position data).

For example, check_card_config should be renamed to reflect the fact that it updates state through init_hands.

Additionally, there is currently a convention of state variables having either no postfix to mean "applies to out-of-position" and postfix _ip to mean "applies to in-position". Variables representing out-of-position traits should be postfixed with _oop to make this distinction clear.

[bkushigian]

Agreed!

I think that some of the _ip postfix vs no postfix isn't quite so straightforward. For instance PostFlopNode::num_elements is always the number of 'elements' the current player has, while PostFlopNode::num_elements_ip is the number of elements IP has, but only on the first node of a street.

It would be good to:

1. figure out exactly why this is needed
2. rename accordingly
3. document :)

[bkushigian]

We should put this into the docs branch as that is where I'm keeping track of all new documentation and clarity renaming changes.

[bkushigian]

Now part of PR #4