[feladat @ 303] Added preliminary support for SPF (other than in TXT) and SSHFP records. Valdiation for these types will be added in near future. As requested in #89.

[feladat @ 302] Applied the patches supplied in #82 and #85. Also quoted some additional values before they are send to the database.

[feladat @ 300] Bugfix: When no zones are available in current listing, it isn't possible to switch to an other listing. Fixed this by displaying the character selection in this case. Closes: #81. Bug reported by Tom Hutchison.