Update README.md

Made requirement for patched Mono to be on PATH clearer
Updated NuSpec to include source for symbol packages, scripted call NuGet,
now takes parameter which is the version number
Updating version to 1.0.3
NuGet package updated to build symbols package, also script added to get
appropriate versions of source for ilmerged dependencies
Preserve IsJson when using transactions
Merge pull request #28 from thinkbeforecoding/master

Preserve IsJson when using transactions
Fixed: incorrectly built midpoint cache in an edge case (asserting failure)
Merge branch 'master' of github.com:EventStore/EventStore
Merge branch 'master' into dev