make most types instances of Data (and Typeable)
This allows them to be pretty-printed with pprint (from data-pprint)
when debugging, and shouldn't have much impact otherwise.
require data-pprint 0.2.3, works with ghc < 7.2
drop some experimental pprint logging
allow an optional level argument with --debug
new debug helpers; --debug=N sets debugLevel

The debug level set by `--debug[=N]` is now available to pure and
startup code as debugLevel, using unsafePerformIO.

`dbg LABEL ...` is now the go-to helper for tracing values on the
console; it produces output when the debug level is non-zero. `dbgExit`
is similar but exits immediately, avoiding further output. The
`dbgshow`, `dbgppshow` and `dbgpprint` variants allow control over the
pretty-printing method and required debug level, allowing more control
over what is displayed when.

Other cleanups: lstrace -> ltrace, pdbgAt -> pdbg, tracewith -> traceWith.
debug level sets amount/journal show verbosity

Amounts and journal values are often rendered too verbosely in debug
output, obscuring what's important. Here we try adjusting the level
of detail in the Show instance based on the global debug level.
Needs more work.
require data-pprint 0.2.3, works with ghc < 7.2
balance: new multi-column reports & documentation

Two new multi-column balance report modes show ending balance per
period: `--cumulative`, starting from 0, and `--historical`, starting
from the historical starting balance.

The balance command's specification has been clarified and consolidated
in the Balance.hs haddock. Reports.hs has also had haddock updates. The
old AccountsReport type is now BalanceReport, still used by
single-column balance report. The new MultiBalanceReport type is used by
the multi-column reports.
fix handling of --debug before command
three fixes to handle --debug=N like --debug
note that getCliOpts, debugArgs api fns are unused
docs: release notes
docs: document multicolumn balance reports
docs: warn about flag/value spacing bug
tools: run functional tests less verbosely