enable gzip compression (for http reponse)
handle error in metafont generation and display error message
timeout mf2outline after 5 seconds

in some cases, the mf2outline script ran longer than the webserver timeout
allowed, which resulted in the webserver returning a response but the python script
going on without being killed.
and furthermore, waiting more than 5 seconds is not reasonable for the end user.
add better errors gem
require libs/gems only for required environments

* sinatra reloader: dev
* time: prod
remove Rack::ShowExceptions (not needed i guess)
handle error for export also

see 1b2159f for the initial implementation on handling the generation error.
this change now handles also the case for font export.

additionally, we first generate the export by ajax and only after redirect to
the download. by adding caching the 2nd call to the same export should not
be a huge overhead.
remove output file before each otf generation

if we leave it, the error check after the generation can be successful even
though the current pass did not succeed and did not generate an otf.
add 404 and 500 pages
catch 404 for non existing pages handler
redirect trailing slash urls
get rid of rack security warning in dev mode
add fetamont font
allow rational numbers in metafont files

e.g. a number 20/30 is valid when defined in font.mf
don't write hidden parameters to mf file
use key for font params

this is actually a bug, as we haven't used the key for mapping the
params from the ui to the db. also, the params were saved with the wrong
name in the db.

we haven't detected this as per coincidence the dasherized names were
equal to the key.
remove special handling for storing yaml

as it seems this is not necessary. maybe with the update of datamapper this
became obsolete. maybe this hasn't worked properly at all.
re-arrange app into new directories

* new config directory for all configs
* everything app related goes into app/ (views, lib, ...)
* models (interaction with db) go into app/models
remove explicit utf-8 file encoding

with ruby 2.0 this is the default now
allow negative parameter ranges