Improves modules sourcing

A module should always begin with a test to `execute_module` to see if
it should be executed. As modules are always sourced
(even when embedded), a simple `return` will stop the subscript.

Modules are executed in a subscript, so the global space will not be
polluted, and will also be reset after the execution of the module.

This commit also solves some bugs in Makefile and lua parser.

scripts/android.sh

@@ -1,4 +1,8 @@
 # Android debug package
+if [[ $(execute_module "android") == false ]]; then
+    return
+fi
+
 init_module "Android"
 
 

scripts/debian.sh

@@ -1,4 +1,8 @@
 # Debian package
+if [[ $(execute_module "debian") == false ]]; then
+    return
+fi
+
 init_module "Debian"
 
 

scripts/example.sh

@@ -1,4 +1,5 @@
 # Example
+return
 
 # This example script should show you how to write a module for love-release.
 

scripts/macosx.sh

@@ -1,4 +1,8 @@
 # Mac OS X
+if [[ $(execute_module "osx") == false ]]; then
+    return
+fi
+
 init_module "Mac OS X"
 
 

scripts/windows.sh

@@ -1,4 +1,8 @@
 # Windows
+if [[ $(execute_module "windows") == false ]]; then
+    return
+fi
+
 init_module "Windows"