reimplement require/include to better support precompilation

the codepaths through these methods were not particularly amenable to adding incremental precompilation.
the problem is that the cache-load code paths need to be mirrors of their non-cache counterparts.
this minimizes the code paths to running "include" to one, and similarly for "reload"/"require"
those are now limited to only handling module names (symbols), rather than arbitrary paths

this also fixes a number of issues with the incremental serializer that
have snuck in over time.

base/client.jl

@@ -274,7 +274,9 @@ let reqarg = Set(UTF8String["--home", "-H",
  end
  # load file immediately on all processors
  if opts.load != C_NULL
- require(bytestring(opts.load))
+ let file = bytestring(opts.load), cwd = pwd()
+ @everywhere include($file, (1, $cwd))
+ end
  end
  # eval expression
  if opts.eval != C_NULL

base/docs/basedocs.jl

@@ -368,7 +368,7 @@ function is typically used to load source interactively, or to
 combine files in packages that are broken into multiple source
 files.
 """
-include_from_node1
+base_include
 
 """
 0 (zero; BrE: `/ˈzɪərəʊ/` or AmE: `/ˈziːroʊ/`) is both a number and the numerical digit used to represent that number in numerals. It fulfills a central role in mathematics as the additive identity of the integers, real numbers, and many other algebraic structures. As a digit, 0 is used as a placeholder in place value systems. Names for the number 0 in English include zero, nought or (US) naught (`/ˈnɔːt/`), nil, or — in contexts where at least one adjacent digit distinguishes it from the letter "O" — oh or o (`/ˈoʊ/`). Informal or slang terms for zero include zilch and zip. Ought and aught (/ˈɔːt/), as well as cipher, have also been used historically.

base/exports.jl

@@ -1097,7 +1097,6 @@ export
  include,
  include_string,
  reload,
- require,
 
 # RTS internals
  finalizer,

base/interactiveutil.jl

@@ -385,7 +385,6 @@ function workspace()
  Expr(:toplevel,
  :(const Base = $(Expr(:quote, b))),
  :(const LastMain = $(Expr(:quote, last)))))
- empty!(package_list)
  empty!(package_locks)
  nothing
 end