Looking for cover in epub2 can fail because there are multiple
cover entries in meta.
Make the parsing more lenient by just checking that at least one
entry has been found, instead of exactly one.
Merge pull request #281 from fdumontmd/pp-cover-fix

Make looking for cover more lenient. Thanks!
Use a loop in BookExtractorBase.correctURIs

Backbone.js uses recursion to process events; for correctURIs, this
causes a problem when the list of positions to fix is large (eventually
the call stack grows too long).

The fix is to add a loop in correctURIs that mimics the behaviour
resulting from the event processing, but in constant stack space.
Small typo fixes in README.md
Merge pull request #282 from fdumontmd/parse-rangeError-fix

Use a loop in BookExtractorBase.correctURIs
Merge pull request #283 from fdumontmd/readme-typo-fix

Small typo fixes in README.md