Introduce blorg: MVP static site generator

hugo is nice - but it's huge. I've never built a static site generator before
and thought the world could use one more - it's not like there's already enough
choice out there!

No, but seriously. I love hugo and it has all the bells and whistles and you
should definitely use that and not this. I just like reinventing the wheel to
learn about stuff - and I like the 80/20 rule. This gives like 60% of what I
want already and is tiny fraction of hugo in terms of LOC (hugo without it's
bazillion dependencies is like 80k+ - this is like 500 and very likely won't
ever grow above let's say 5k).

Also org mode is awesome and why not use it as a configuration format as
well. Let's see where this goes. YOLO.

blorg/page.go

@@ -0,0 +1,83 @@
+package blorg
+
+import (
+	"fmt"
+	"html/template"
+	"os"
+	"time"
+
+	"github.com/niklasfasching/go-org/org"
+)
+
+type Page struct {
+	*Config
+	Document       *org.Document
+	Info           os.FileInfo
+	PermaLink      string
+	Date           time.Time
+	Content        template.HTML
+	BufferSettings map[string]string
+}
+
+func NewPage(c *Config, path string, info os.FileInfo) (*Page, error) {
+	f, err := os.Open(path)
+	if err != nil {
+		return nil, err
+	}
+	d := c.OrgConfig.Parse(f, path)
+	content, err := d.Write(getWriter())
+	if err != nil {
+		return nil, err
+	}
+	date, err := time.Parse("2006-01-02", d.Get("DATE"))
+	if err != nil {
+		date, _ = time.Parse("2006-01-02", "1970-01-01")
+	}
+	return &Page{
+		Config:         c,
+		Document:       d,
+		Info:           info,
+		Date:           date,
+		Content:        template.HTML(content),
+		BufferSettings: d.BufferSettings,
+	}, nil
+}
+
+func (p *Page) Render(path string) error {
+	f, err := os.Create(path)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+	templateName := "item"
+	if v, ok := p.BufferSettings["TEMPLATE"]; ok {
+		templateName = v
+	}
+	t := p.Template.Lookup(templateName)
+	if t == nil {
+		return fmt.Errorf("cannot render page %s: unknown template %s", p.Info.Name(), templateName)
+	}
+	return t.Execute(f, toMap(p.BufferSettings, p))
+}
+
+func (p *Page) Summary() template.HTML {
+	for _, n := range p.Document.Nodes {
+		switch n := n.(type) {
+		case org.Block:
+			if n.Name == "SUMMARY" {
+				w := getWriter()
+				org.WriteNodes(w, n.Children...)
+				return template.HTML(w.String())
+			}
+		}
+	}
+	for i, n := range p.Document.Nodes {
+		switch n.(type) {
+		case org.Headline:
+			w := getWriter()
+			org.WriteNodes(w, p.Document.Nodes[:i]...)
+			return template.HTML(w.String())
+		}
+	}
+	return ""
+}