added include/3 example to homepage #106
added padding around code examples #106
use java.nio.file.Files
ensure ensure_loaded/1 does not re-load already loaded files - resolves #99
log warnings and memory usage as part of running system tests
use WeakHashMap - resolves #102
remove unnecessary variable
javadoc
comment
include in code examples any output from failed evaluation attempts
put comments of code examples in paragraph tags #106
when generating manual.html group commands by their packages and add descriptions - #106

The description for a group of commands is read from the corresponding
package-info.java file.
SysTestParser tests
removed unused variable
override calculate(Term... args)
removed unused variable
exception message
error messages (removed leading space from start of query)
run build-utils tests as part of unit-test target
updated directory structure description