Release 0.6.3 "Come and See": Repair test suite

The focus of this release was to reactivate the test suite and fix the problems that were found activating it.

New features:

• HMS and DMS operations
• unit: Rendering of dms and hms units
• Allow · as a multiplication sign in equations
• ui: Display 'E' cursor inside parentheses
• graphics: Accept based integers as position for DrawText
• complex: Add setting to switch between 2+3i and 2+i3.

Bug fixes:

• decimal: Fix precision loss for addition with carry
• Base: limit range of bases to 2-36
• files: Do not add a trailing zero when reading a text file
• decimal: Adjust MinimumSignificantDigits behaviour
• units: Do not auto-simplify 1.0 during conversion
• decimal: Normalize parsed numbers
• solver: Fix sign error in epsilon exponent for solve/integrate
• parser: Accept x! as input
• simulator: Avoid faulty break-through in switch statement
• complex: Make tag higher-priority than complex
• editor: Adjust cursor and select correctly during replace
• decimal: Fix display of 0.2 in NoTrailingDecimal mode
• complex: Save this in a GC pointer when it can move
• arithmetic: Do not fail because of surrounding error
• decimal: Clamp int32 conversions from decimal
• commands: Parse exp10 correctly in expressions
• decimal: Avoid infinite loop computing expm1
• ids: Do not allow parsing of structures
• dmcp: Make sure the tests don't block on wait_for_key
• decimal: Use correct angle unit for negative gamma values

Improvements:

• settings: Add classes that save/restore a given setting
• Add XSHIFT to shift to XSHIFT state directly
• Add NOSHIFT constant to simplify test writing
• ui: Add a variant of close_editor without trailing zero
• decimal: Cache gamma_ck values (accelerate gamma and lgamma)
• Replace magic constant -1 with EXIT_PGM
• doc: Record performance data for 1000 iterations of SumTest
• decimal: Add tracing for gamma / lgamma function

New tests:

• Add tests for arithmetic truncation on short bitsizes
• Add tests for on-line help
• Add test for plotting flags
• Add test for Unicode to text conversions
• Add test for rectangular complex display options
• Add tests for plot scaling functions
• Add tests for the sorting functions
• Add test for parsing text with quotes inside
• Add test for file-based STO and RCL
• Add test for 2^256 computation (buf #460)
• Fix indentation of [PASS] or [FAIL] for UTF8 characters
• Add tests for units and conversions
• Add a keyboard test checking the single-colon insert in text
• Add test for i*i=-1 auto-simplification
• Add basic test for numerical integration
• Add test for fraction formats
• Add solver test
• Add missing tests
• Add test for immediate STO (#390)
• Add tests for the Cycle command
• Add test for catalog feature
• Add test for "smart" keyboard shortcuts introduced in 0.4.6
• Add regression test for #371
• Add tests for editor operations
• Test stack operations
• Add test for GXor, GOr and GAnd
• Add test for ResetModes
• Add plotting test for every decimal function
• Add image checking for graphical tests
• Add tests for graphic and text drawing commands
• Make it possible to individually run tests.
• Add plotting tests
• Add test parsing the various spellings for commands

Full Changelog: v0.6.1...v0.6.3