secret-handshake: add hint to @Ignore annotations

difference-of-squares: add hint to @Ignore annotation

space-age: add hint to @Ignore annotations

gigasecond: add hint to @Ignore annotations

pangram: add hint to @Ignore annotations

saddle-points: add hint to @Ignore annotations per #440

perfect-numbers: add hint to @Ignore annotations per #444

ref #448

Ref. #448

Ref. #448

Fixes: #440

Fixes: #444

triangle: fix mistake in test name

Fixes: #419

all-your-base: add hint to @Ignore annotations

allergies: add hint to @Ignore annotations

anagram: add hint to @Ignore annotations

acronym: add hint to @Ignore annotations

accumulate: add hint to @Ignore annotations

isogram: rate difficulty 4, reposition

isogram: fix build issues

The test file was trying to import the example code which it shouldn't
do. Also removed unneeded package declarations and renamed the test
file to be consistent.

saddle-points: add to track

rna-transcription: add hint to Ignore annotation