Add Makefile targets: devenv, envtest

Makefile

@@ -1,5 +1,5 @@
 PREFIX = /home/heck/local-default/
-DEBUG = 0
+DEBUG = 1
 BUILD_DIR = ./build
 
 BUILD_EXT_OPTS = --prefix=$(PREFIX)
@@ -8,7 +8,7 @@ ifeq ($(DEBUG),1)
 	BUILD_EXT_OPTS+=--debug
 endif
 
-.PHONY: all build clean
+.PHONY: all build clean devenv envtest
 
 all: build_ext
 
@@ -17,3 +17,12 @@ build_ext:
 
 clean:
 	rm -r $(BUILD_DIR)
+
+devenv:
+	LD_LIBRARY_PATH=$(PREFIX)/lib \
+	PYTHONPATH=`pwd`/build/lib.linux-x86_64-3.7:\
+	`pwd`/src \
+	bash -l
+
+envtest:
+	python3 -c 'import pEp'