Change some checks

lib/main.sh

@@ -123,21 +123,21 @@ envbot_quit() {
 }
 
 # Check for moreutils else we're doomed.
-if ! which sponge
+if [[ ! -x /usr/bin/sponge ]]
 then
     echo "moreutils is a dep, please install."
     envbot_quit 1
 fi
 
-# Check for w3m because we use it to convert html entities.
-if ! which w3m
+# Check for links because we use it to convert html entities.
+if [[ ! -x /usr/bin/links ]]
 then
-    echo "w3m is a dep, please install."
+    echo "links is a dep, please install."
     envbot_quit 1
 fi
 
 # Check for recode
-if ! which recode
+if [[ ! -x /usr/bin/recode ]]
 then
     echo "recode is a dep, please install."
     envbot_quit 1