Fix problem with logical and/or giving parser errors
Fix problem with logical and/or giving parser errors

Problem is that parsers for '&' and '|' consume an character and then
they fail when they encounter another '&' or '|' character. Fix this by
using lookahead to see if the next character is a '&' or '|' and if it
is then fail without consuming any input.

mbudde/jana,mbudde/jana,tyoko-dev/jana,tyoko-dev/jana,tyoko-dev/jana,mbudde/jana,tyoko-dev/jana,mbudde/jana