General cleanup of spacing and order

Preparing to rework the pipelining algorithm
Removed unneccessary safe_fixtable for ordered set

Via ets man page:
Note that for tables of the ordered_set type, safe_fixtable/2 is not
necessary as calls to first/1 and next/2 will always succeed
Replaced local size in state with ets lookup

Got rid of duplicated information in order to
reduce complexity and change points for upcoming
algorithm changes.
Removed unnecessary pipeline size from con state

Tracking size in http connection process state
was unnecessary as it wasn't queried for logic
or obvious reporting and ets table should have
right (within 1) value already.
Encapsulated conn ets table use in ibrowse_lb

Moved all interactions with ets table tracking
connections to API functions on ibrowse_lb,
to reduce knowledge of ets table and its structure.

Also fixed "bug" where ceiling for pipelining
threshold was different than the set value for increment;
made them the same.