mark disk_usage spec pending
add specs for current_catalog
add some tests for filtering.
all hail the omnipotent rubocop
raise an exception on missing JournalEntry method if the user passed arguments to it.
If you can't fix it, ignore it.
install systemd when running travis
install to default directories
__dir__ is ruby 2.0 specific
Merge pull request #47 from ledbettj/travis

install systemd when running travis
add spec for Systemd::JournalEntry
add explicit test for filtering with AND.
add specs for cursor/seek
more seek() specs
add wrappers for sd_journal_get{realtime,monotonic}_usec
dont include a useless FFI ptr string in monotonic read.
Merge pull request #48 from ledbettj/entry-timestamps

Entry timestamps
add log_stream (wrapping sd_journal_stream_fd)
allow file: instead of files: and ensure that value is an array.
add specs for move()