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/expressions.wren

@@ -0,0 +1,35 @@
+// retoor <retoor@molodetz.nl>
+
+import "jinja" for Environment, DictLoader
+
+var env = Environment.new(DictLoader.new({
+  "math": "{{ 2 + 3 * 4 }}",
+  "paren": "{{ (2 + 3) * 4 }}",
+  "mod": "{{ 10 \% 3 }}",
+  "div": "{{ 10 / 4 }}",
+  "neg": "{{ -5 }}",
+  "compare_chain": "{\% if 1 < 2 and 2 < 3 \%}yes{\% endif \%}",
+  "bool_and": "{{ true and false }}",
+  "bool_or": "{{ true or false }}",
+  "bool_not": "{{ not false }}",
+  "string_in": "{\% if \"b\" in \"abc\" \%}found{\% endif \%}",
+  "list_in": "{\% if 2 in [1, 2, 3] \%}found{\% endif \%}",
+  "nested_access": "{{ data.items[0].name }}",
+  "filter_chain": "{{ text|trim|upper }}",
+  "method_call": "{{ items|join(\", \")|upper }}"
+}))
+
+System.print(env.getTemplate("math").render({})) // expect: 14
+System.print(env.getTemplate("paren").render({})) // expect: 20
+System.print(env.getTemplate("mod").render({})) // expect: 1
+System.print(env.getTemplate("div").render({})) // expect: 2.5
+System.print(env.getTemplate("neg").render({})) // expect: -5
+System.print(env.getTemplate("compare_chain").render({})) // expect: yes
+System.print(env.getTemplate("bool_and").render({})) // expect: false
+System.print(env.getTemplate("bool_or").render({})) // expect: true
+System.print(env.getTemplate("bool_not").render({})) // expect: true
+System.print(env.getTemplate("string_in").render({})) // expect: found
+System.print(env.getTemplate("list_in").render({})) // expect: found
+System.print(env.getTemplate("nested_access").render({"data": {"items": [{"name": "test"}]}})) // expect: test
+System.print(env.getTemplate("filter_chain").render({"text": "  hello  "})) // expect: HELLO
+System.print(env.getTemplate("method_call").render({"items": ["a", "b", "c"]})) // expect: A, B, C