Improve naming of ReadStdin

We don't need to say everything twice, methods are already prefixed
with “read”.
Merge pull request #3382 from soc/topic/std-in

Improve naming of ReadStdin
Expose seq field for variable arity definitions

In 2.11 we've changed TupleClass, ProductClass and FunctionClass
endpoints to be exposed as (Int => Symbol) functions that never throw
exceptions but rather return NoSymbol instead of previous error-prone
indexed access on array that could explode.

While simplifying one use case (indexed access) it complicated
ability to check if symbol at hand is in fact a tuple, product or
function:

  (1 to 22).map(TupleClass).toList.contains(symbol)

To cover this extra use case we add a seq method to the variable arity
class definitions that exposes a corresponding sequence of class symbols:

  TupleClass.seq.contains(symbol)
Merge pull request #3398 from densh/topic/var-arity-class-seq

Expose seq field for variable arity definitions
an optimization for c.eval

People are very frequently using c.eval in order to obtain underlying
values of literals. Spinning up a new compiler for that modest purpose
is a gross waste of fossil fuels.
Merge pull request #3399 from xeno-by/topic/eval

an optimization for c.eval
SI-6879 improves Context.freshName

Instead of per-compilation unit unique counters, the freshName API now
uses a per-Global counter. Fresh names now also contain dollars to exclude
clashes with supported user-defined names (the ones without dollar signs).

This doesn’t fix the bug, because per-Global counters get created anew
every time a new Global is instantiated, and that provides some potential
for name clashes even for def macros, but at least it completely excludes
clashes in typical situations.
addresses pull request feedback
Merge pull request #3401 from xeno-by/topic/fresh

SI-6879 improves Context.freshName