Merge pull request #40 from Carreau/master

tooltip on in-place functions, julia lang hint in metadata
grammatical cleanups in comments
print build messages to STDERR, to match other Pkg messages
replace PDF logo with SVG logo, install alongside PNG version
fix merge conflict
use Base.convert to parse VersionNumber, duh
use logo in README
build.jl cleanups, change IJulia to a different port than IPython's kernel (fixes #41)
note Tornado dependency (thanks @ViralShah)
bugfix in tooltip (object_info_request) - look up in Main namespace, not in IJulia
bugfix in tooltip (object_info_request) - handle qualified names via parse rather than symbol
unbreak Symbol return values a second time (sigh, redoing commit 9f756d391d91646995d7ecf0791aa613d655f25c)
note pyzmq dependency (fixes #46)
flush stdio and display before pyout, fixes #44
no need for vprintln here, since send_ipython already prints message in verbose mode
change vprintln to a macro so that we don't evaluate the arguments (which in some cases would involve constructing large strings) in the common case of non-verbose mode
implement ;... shell-escaping (fixes #43)
use repl_cmd rather than run for "; ..." commands, as discussed in #43
interpret cell beginning with ? as Base.@help request, similar to Julia REPL
give error when non-functional hmac is found; see loladiro/GnuTLS.jl#5