allow spaces in custom env settings

[5andr0]

This patch will allow multiple arguments and spaces for custom settings.

some examples of settings requiring multiple arguments:

ClientTransportPlugin obfs4 exec /usr/bin/obfs4proxy managed
bridge obfs4 141.201.27.48:420 gibberish cert=more-gibberish iat-mode=0
ReachableAddresses accept *:80

for env in $(printenv | grep '^TOR_'); do
The for loop uses space as a delimiter unless IFS is set to '\n'
Another problem here is that arguments other than [0-9]+|false|true are encapsulated in quotes which will not work for those settings.
In fact, there is not a single torrc setting that requires quotes. And even if necessary, the quotes could be added inside the environment var instead of forcing them on all non boolean/decimal values.