Defer bundle loading to antigen-apply command (#513)

* Defer bundle loading to `antigen-apply` command
* Using HEREDOC rather than string concat
* Properly directing error messages
* Handle directory locations, add tests
* Remove compdump on antigen-reset
* Apply deferred compdef after bundle sourcing
* Only use cache in non-interactive mode
* Refactor load to support themes, support prezto function loading
* Re-added compatibility code for antigen-theme (fails with antigen-reset)

Makefile

@@ -8,6 +8,7 @@ BIN 	  ?= ${PROJECT}/bin
 SRC       ?= ${PROJECT}/src
 TESTS     ?= ${PROJECT}/tests
 TOOLS     ?= ${PROJECT}/tools
+TEST      ?= ${PROJECT}/tests
 
 ZSH_VERSION 	?= zsh-5.3
 CONTAINER_ROOT  ?= /antigen
@@ -81,7 +82,7 @@ itests:
 	@${MAKE} tests CRAM_OPTS=-i
 
 tests:
-	@${MAKE} .container COMMAND="sh -c 'ZDOTDIR=${TESTS} ANTIGEN=${PROJECT} cram ${CRAM_OPTS} --shell=zsh ${TESTS}'"
+	@${MAKE} .container COMMAND="sh -c 'ZDOTDIR=${TESTS} ANTIGEN=${PROJECT} cram ${CRAM_OPTS} --shell=zsh ${TEST}'"
 
 stats:
 	@${MAKE} .container COMMAND="${TOOLS}/stats --zsh zsh --antigen ${PROJECT}"

README.mkd

@@ -622,7 +622,8 @@ to activate it, useful when debugging failing bundle installs.
 ### Customizations
 
 `ANTIGEN_CACHE` — This configures the path to the cache init file, where
-Antigen stores it's cached bundles. Defaults to `$ADOTDIR/init.zsh`.
+Antigen stores it's cached bundles. Defaults to `$ADOTDIR/init.zsh`. Set to `false`
+to disable caching mechanism.
 
 `ANTIGEN_COMPDUMP` — Use this configuration to define where [zsh's completion
 system](http://zsh.sourceforge.net/Doc/Release/Completion-System.html#Initialization) should store completion's dump file. Defaults to `$ADOTDIR/.zcompdump`.