Fix more unbound variables (#34)

Author: nkakouros

lib/UI/Color.sh

@@ -74,7 +74,7 @@ else
   alias UI.Color.NoInvisible="echo"
 fi
 
-alias UI.Powerline.IsAvailable="UI.Color.IsAvailable && test -z \$NO_UNICODE && (echo -e $'\u1F3B7' | grep -v F3B7) &> /dev/null"
+alias UI.Powerline.IsAvailable="UI.Color.IsAvailable && test -z \${NO_UNICODE-} && (echo -e $'\u1F3B7' | grep -v F3B7) &> /dev/null"
 if UI.Powerline.IsAvailable
 then
   alias UI.Powerline.PointingArrow="echo -e $'\u27a1'"

lib/UI/Color.var.sh

@@ -76,7 +76,7 @@ else
   UI_Color_NoInvisible=""
 fi
 
-alias UI.Powerline.IsAvailable="UI.Color.IsAvailable && test -z \$NO_UNICODE && (echo -e $'\u1F3B7' | grep -v F3B7) &> /dev/null"
+alias UI.Powerline.IsAvailable="UI.Color.IsAvailable && test -z \${NO_UNICODE-} && (echo -e $'\u1F3B7' | grep -v F3B7) &> /dev/null"
 if UI.Powerline.IsAvailable
 then
   UI_Powerline_PointingArrow=$'\u27a1'

lib/oo-bootstrap.sh

@@ -4,7 +4,7 @@
 ### BOOTSTRAP FUNCTIONS ###
 ###########################
 
-if [[ -n "$__INTERNAL_LOGGING__" ]]
+if [[ -n "${__INTERNAL_LOGGING__:-}" ]]
 then
   alias DEBUG=":; "
 else
@@ -132,7 +132,7 @@ System::SourceFile() {
   then
     ## if already imported let's return
     # if declare -f "Array::Contains" &> /dev/null &&
-    if [[ "${__oo__allowFileReloading}" != true ]] && [[ ! -z "${__oo__importedFiles[*]}" ]] && Array::Contains "$libPath" "${__oo__importedFiles[@]}"
+    if [[ "${__oo__allowFileReloading-}" != true ]] && [[ ! -z "${__oo__importedFiles[*]}" ]] && Array::Contains "$libPath" "${__oo__importedFiles[@]}"
     then
       # DEBUG subject=level3 Log "File previously imported: ${libPath}"
       return 0