Fixes in 2018/ciura/README.md + Makefile

Formatting fixes and possibly typos (but mostly formatting).

On bold code blocks: I removed the bold because it appeared that some of
the formatting was messed up. I think this is okay though rather than
trying to fix the formatting of bold code blocks.

Set alt related target variables in Makefile so that make alt actually
works.

2018/ciura/Makefile

@@ -113,8 +113,8 @@ CSRC= ${PROG}.o
 DATA=
 TARGET= ${PROG}
 #
-ALT_OBJ=
-ALT_TARGET=
+ALT_OBJ= ${PROG}.alt.o
+ALT_TARGET= ${PROG}.alt
 
 
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