Clarify the common targets and their actions.

Slightly edited these targets (release, debug, all) for consistency.
Also picked some nits in comments and 'make help'.

Makefile

@@ -48,7 +48,7 @@ PROJECTFILE = $(or $(wildcard project*.cpp), nomain.cpp)
 # If main() is in another file delete the line above, edit and uncomment below
 #PROJECTFILE = mymainfile.cpp
 
-# name of the tar ball created for submission
+# name of the tarball created for submission
 PARTIAL_SUBMITFILE = partialsubmit.tar.gz
 FULL_SUBMITFILE = fullsubmit.tar.gz
 
@@ -61,13 +61,13 @@ CXXFLAGS = -std=c++1z -Wconversion -Wall -Werror -Wextra -pedantic
 # make release - will compile "all" with $(CXXFLAGS) and the -O3 flag
 #				 also defines NDEBUG so that asserts will not check
 release: CXXFLAGS += -O3 -DNDEBUG
-release: all
+release: $(EXECUTABLE)
 
 # make debug - will compile "all" with $(CXXFLAGS) and the -g flag
 #              also defines DEBUG so that "#ifdef DEBUG /*...*/ #endif" works
 debug: EXECUTABLE := $(DEBUG)
 debug: CXXFLAGS += -g3 -DDEBUG
-debug: clean all
+debug: clean $(EXECUTABLE)
 
 # make profile - will compile "all" with $(CXXFLAGS) and the -pg flag
 profile: CXXFLAGS += -pg
@@ -78,8 +78,10 @@ profile: clean all
 static:
 	cppcheck --enable=all --suppress=missingIncludeSystem $(SOURCES) *.h *.hpp
 
-# highest target; sews together all objects into executable
-all: $(EXECUTABLE)
+# Build both release and debug executables
+all: clean
+	make -Rr release
+	make debug
 
 $(EXECUTABLE): $(OBJECTS)
 ifeq ($(EXECUTABLE), executable)
@@ -167,8 +169,8 @@ EECS281 Advanced Makefile Help
            $$ make test3
            $$ make alltests        (this builds all test drivers)
     C) If test drivers need special dependencies, they must be added manually.
-    D) IMPORTANT: NO SOURCE FILES THAT BEGIN WITH test WILL BE ADDED TO ANY
-       SUBMISSION TARBALLS.
+    D) IMPORTANT: NO SOURCE FILES WITH NAMES THAT BEGIN WITH test WILL BE
+       ADDED TO ANY SUBMISSION TARBALLS.
 
 * Static Analysis support
     A) Matches current autograder style grading tests