robot-simulator: add hints to @Ignore annotations

minesweeper: add hints to @Ignore annotations

sublist: add hints to @Ignore annotations

CustomSetTest : add hint to @Ignore annotations

Clock : add hint to @Ignore annotations

ChangeCalculatorTest : add hint to @Ignore annotations

ListOpsTest : add hint to @Ignore annotations

simple-cipher: add hint to @Ignore annotations

palindrome-products: add hint to @Ignore annotations

#442

#443

#445

#445

#445

#446

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.