A new chapter, src/devtools. ConnectionManager lists saved connections
with their engine and address, or why one failed, and connects on Enter;
ConnectionForm fills a connection with a port checked from 1 to 65535,
tests it and saves it. SchemaTree shows schemas, tables, views and
fields with keys marked; ERDiagram draws tables and their foreign keys
on NodeGraph, whose fixed wires show only the sockets that hold one.
QueryHistory finds past runs and runs one again; QueryPlanViewer shows
each step's share of the cost. TableStructureEditor edits fields in
place; IndexManager lists and draws up indexes; RedisKeyBrowser finds
keys by glob and lays out each type. QueryEditor is editor::CodeEditor,
whose lexer now knows SQL's words, and QueryResultGrid is
tables::DataGrid. lists::row_action keeps a row's button its own.
ZacharyZhang-NY
c137ddb0f7