feat: add cJSON and SQLite amalgamation source files under deps/

Add the cJSON library (cJSON.c, cJSON.h) and SQLite amalgamation
(sqlite3.c, sqlite3.h, sqlite3ext.h, shell.c) as vendored dependencies
in the deps/ directory for use by the project build system.

test/jinja/macros.wren

@@ -0,0 +1,15 @@
+// retoor <retoor@molodetz.nl>
+
+import "jinja" for Environment, DictLoader
+
+var env = Environment.new(DictLoader.new({
+  "simple": "{\% macro greet(name) \%}Hello {{ name }}!{\% endmacro \%}{{ greet(\"World\") }}",
+  "with_default": "{\% macro greet(name, greeting=\"Hi\") \%}{{ greeting }} {{ name }}!{\% endmacro \%}{{ greet(\"Bob\") }}",
+  "multiple_calls": "{\% macro item(x) \%}[{{ x }}]{\% endmacro \%}{{ item(1) }}{{ item(2) }}{{ item(3) }}",
+  "with_loop": "{\% macro items(list) \%}{\% for i in list \%}{{ i }}{\% endfor \%}{\% endmacro \%}{{ items([1, 2, 3]) }}"
+}))
+
+System.print(env.getTemplate("simple").render({})) // expect: Hello World!
+System.print(env.getTemplate("with_default").render({})) // expect: Hi Bob!
+System.print(env.getTemplate("multiple_calls").render({})) // expect: [1][2][3]
+System.print(env.getTemplate("with_loop").render({})) // expect: 123