clonebundles: move a bundle of clone bundle related code to a new module
In the process on general clone bundle automatically, we need to make some
function available more widely. This is a good opportunity to extract a
significant amount of code from `mercurial.exchange` into a new
`mercurial.bundlecaches`. This make `mercurial.exchange` move under the 3K line
range (hooray…).
The module is called `bundlecaches` because I expect it to be eventually useful
for more than just clone bundle (like pull bunbles).
Differential Revision: https://phab.mercurial-scm.org/D9208
{
// Enforcing
"eqeqeq" : true, // true: Require triple equals (===) for comparison
"forin" : true, // true: Require filtering for..in loops with obj.hasOwnProperty()
"freeze" : true, // true: prohibits overwriting prototypes of native objects such as Array, Date etc.
"nonbsp" : true, // true: Prohibit "non-breaking whitespace" characters.
"undef" : true, // true: Require all non-global variables to be declared (prevents global leaks)
// Environments
"browser" : true // Web Browser (window, document, etc)
}