Uniformize all the command function in lektor

Closes #101 (closed)

CHANGELOG.md

@@ -15,6 +15,7 @@
 - Fix: can now interpret the *add* commands with spaces in the query correctly
 - Fix: no more segv when copying a null URI
 - Fix: when no screen is detected with `lkt`, the large screen behaviour is used to not break other commands like `wc`
+- Change: all the functions in the command trie have the same signature (less bloat here)
 - Change: the fields `database/{types,categories,languages}` must now only contain alpha characters and commas, nothing else!
 - Change: reduce the number of regex creation in the populate database from disk part of the code
 - Change: autotools to cmake toolchain