#160: Write unit tests for SQLSearch

[aaronhktan]

Description

• This commit adds tests for the SQLSearch class.
• This commit fixes some logic in SegmentPinyin/SegmentJyutping involving
  glob characters, where invalid sequences before glob characters would
  not be added to the search term.
• This commit fixes the parsing of the 'direct' field in sentence
  links. Since SQLite stores booleans as integers, QJsonValue::toBool()
  would always return "false", even if the stored value was 1.
• This commit adds comparison of definitions and sentences when
  checking for equality in the Entry class.
• This commit adds additional data members to operator<< in Entry et al.
• This commit adds the ability to remove all database connections, which
  is useful on Windows since we cannot delete a database file that somebody
  is keeping a connection open to.

Part of a series of commits for #160.

Type of change

• New feature (non-breaking change which adds functionality)

How Has This Been Tested?

Tested on all three platforms.

PASS	Executing test case TestSqlSearch
	Qt version: 5.15.12
	Qt build: Qt 5.15.12 (arm64-little_endian-lp64 shared (dynamic) release build; by Clang 15.0.0 (clang-1500.0.40.1) (Apple))
	QTest version: 5.15.12
PASS	Executing test function initTestCase
PASS	TestSqlSearch::initTestCase
	Execution took 0.038041 ms.
PASS	Executing test function searchSimplified
PASS	TestSqlSearch::searchSimplified
	Execution took 3.75446 ms.
PASS	Executing test function searchSimplifiedNoResults
PASS	TestSqlSearch::searchSimplifiedNoResults
	Execution took 1.11429 ms.
PASS	Executing test function searchTraditional
PASS	TestSqlSearch::searchTraditional
	Execution took 2.98029 ms.
PASS	Executing test function searchTraditionalNoResults
PASS	TestSqlSearch::searchTraditionalNoResults
	Execution took 0.9655 ms.
PASS	Executing test function searchJyutping
PASS	TestSqlSearch::searchJyutping
	Execution took 5.23442 ms.
PASS	Executing test function searchJyutpingNoResults
PASS	TestSqlSearch::searchJyutpingNoResults
	Execution took 1.93096 ms.
PASS	Executing test function searchPinyin
PASS	TestSqlSearch::searchPinyin
	Execution took 5.00858 ms.
PASS	Executing test function searchPinyinNoResults
PASS	TestSqlSearch::searchPinyinNoResults
	Execution took 1.70817 ms.
PASS	Executing test function searchEnglish
PASS	TestSqlSearch::searchEnglish
	Execution took 3.71446 ms.
PASS	Executing test function searchEnglishNoResults
PASS	TestSqlSearch::searchEnglishNoResults
	Execution took 0.59975 ms.
PASS	Executing test function searchAutoDetect
PASS	TestSqlSearch::searchAutoDetect
	Execution took 19.7345 ms.
PASS	Executing test function searchAutoDetectNoResults
PASS	TestSqlSearch::searchAutoDetectNoResults
	Execution took 2.96712 ms.
PASS	Executing test function searchUnique
PASS	TestSqlSearch::searchUnique
	Execution took 0.923375 ms.
PASS	Executing test function searchTraditionalSentences
PASS	TestSqlSearch::searchTraditionalSentences
	Execution took 0.373875 ms.
PASS	Executing test function cleanupTestCase
PASS	TestSqlSearch::cleanupTestCase
	Execution took 0.001458 ms.
	Test execution took 51.1339 ms.

Checklist:

• My code follows the style guidelines of this project (black for Python
  code, .clang-format in the src/jyut-dict directory for C++)
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have translated my user-facing strings to all currently-supported languages
• I have made corresponding changes to the documentation